Contra Costa County, CA Sign Regulations: Window Signs (2026)
Key Facts
- Window sign area limit
- 10% of the window's area
- Wall sign area limit
- 10% of wall area, same section
- Sign permit required
- Yes, before placement (§88-6.402)
- Single-family lots
- Window signs barred except exempt signs
- Reviewing official
- County zoning administrator
- Governing ordinance
- Ord. No. 2022-03, adopted 5-24-22
Summary
Contra Costa County limits any window sign on private property in the unincorporated area to ten percent of the window's area, the same cap the county sets for wall signs. The rule sits inside the county's 2022 sign ordinance, which also requires a sign permit before a window sign goes up and bars window signs outright on most residential lots.
A projecting, shingle, wall, or window sign must meet all of the following requirements.
(a)Area.(1)No projecting sign may have an area that exceeds five square feet.(2)No shingle sign may have an area that exceeds five square feet.(3)No wall sign may have an area that exceeds ten percent of the area of the wall on which it is placed, excluding the area of all other signs on the frontage of the building.(4)No window sign may have an area that exceeds ten percent of the area of the window on which it is placed.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Ordinance Code: Supplement 103).
Full Breakdown
Section 88-6.612(a) of the Ordinance Code sets area limits for every attached sign type on private property: a projecting or shingle sign may not exceed five square feet, a wall sign may not exceed ten percent of the wall it is mounted on, and a window sign may not exceed ten percent of the window on which it is placed. Attached signs also cannot rise above the eaves, fascia, or parapet of the building, and a wall sign specifically may not exceed fifteen feet in height above grade.
Location matters as much as size. Section 88-6.608 lets a compliant sign go up in most zoning districts, but bars every sign, window signs included, from a lot in a single-family residential district (R-6 through R-100) or the F-1 water recreational district, unless the sign is exempt under Section 88-6.418 or 88-6.606, for example a temporary sign of up to sixty days and twelve square feet. In two-family and multi-family districts (D-1, M-6 through M-29), Section 88-6.608(c) permits only a freestanding or monument sign and one wall sign, still no window sign. That leaves window signs as a practical option mainly for storefronts in commercial and mixed-use districts.
A sign permit is required under Section 88-6.402 before any sign is constructed, placed, or displayed, with the application fee set by the Board of Supervisors and the application reviewed by the zoning administrator under Section 88-6.408. Both the size cap and the district restriction come from the county's 2022 rewrite of the sign chapter, Ordinance No. 2022-03, adopted May 24, 2022.
Violations & Fines
An oversized or unpermitted window sign is an illegal sign under Chapter 88-6, and Section 88-6.408(b)(1) blocks approval of any new sign permit for the lot until that violation is corrected. The county can also pursue the sign as a public nuisance under the Uniform Public Nuisance Abatement Procedure in Chapter 14-6: a written notice and order to correct or remove it, an appeal window to the Board of Supervisors, and abatement costs billed to the owner, with a lien if unpaid after forty-five days.
Frequently Asked Questions
How large can a window sign be in unincorporated Contra Costa County?
Can a homeowner put a sign in a front window in a residential zone?
Do businesses need a permit before installing a window sign?
Sources & Official References
Other rules in Contra Costa County
California rules heatmap·Compare Contra Costa County to another location·View the California sign regulations overview
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